Atrial Fibrillation (AFib)

Ventricular fibrillation and atrial fibrillation are two examples of arrhythmias. Atrial fibrillation may increase the risk of a stroke.

• Atrial fibrillation (AFib) is an irregular heartbeat (arrhythmia) often, but not always, resulting in a fast heartbeat (greater than 100 bpm) at rest.
• Causes of AFib are numerous and include
  • overactive thyroid,
  • alcohol use,
  • pulmonary embolism (a blood clot in the lungs),
  • pneumonia,
  • heart valve disease,
  • coronary artery disease, and
  • many others that result in an abnormal electrical impulse that makes the upper chambers (atrial) contractions of the heart irregular, disorganized and commonly, very rapid.
• Although some people have no symptoms of atrial fibrillation, others may have numerous symptoms, including:
  • palpitations (a sensation of rapid and irregular heartbeat),
  • dizziness or lightheadedness,
  • weak feeling,
  • shortness of breath,
  • chest pain and/or angina,
  • nausea.
• Diagnosis of AFib is begun with the patient's history and physical exam; simply listening to the heartbeat is often enough for a preliminary diagnosis. Usually, an electrocardiogram (ECG or EKG) is done to help distinguish atrial fibrillation from other arrhythmias. Other diagnostic tests may include the following: Holter monitor, event recorder, echocardiogram, stress test, chest X-ray, and blood tests.
• Treatment for AFib is variable and depends upon the patient's condition; three goals are usually attempted; first is medication -- cardiac rate control (slowing down the ventricular rate if it is fast), second is to restore and maintain normal cardiac rhythm, and finally, to prevent clot formation (a common complication of untreated atrial fibrillation).
  • Alternatively, some patients benefit from cardioversion (electrical current is used to shock the heart back to sinus rhythm), catheter ablation (a technique that threads a catheter into the heart's atrium and with attachments that deliver radiofrequency energy) or cryoablation (freezing) to disable or kill cells responsible for generating the abnormal signals.
  • Infrequently, a pacemaker needs to be placed; others may require maze surgery that surgically interrupts the cardiac signaling mechanism between the atria and ventricles.
  • Prevention of blood clots with anticoagulants like warfarin or dabigatran
  • Left atrial appendage closure also to prevent clots from forming
• Complications of AFib are serious. The most dangerous complication of atrial fibrillation is a stroke. Other serious complications can be heart failure and different arrhythmias.
• People can reduce their risk for developing AFib by some lifestyle changes.

Patients who notice that their heartbeats are abnormally fast, slow, or irregular may be experiencing irregular electrical impulses termed arrhythmia.

Atrial fibrillation (also referred to as AFib, Afib, A-fib, and AF) is an irregular and often rapid heart rhythm; the two upper chambers (atria) beat out of coordination with the ventricles (lower chambers). The irregular rhythm, or arrhythmia, results from abnormal electrical impulses in the upper chambers (atria, singular=atrium) of the heart that cause the heartbeat (ventricle contraction) to be irregular and usually fast. The abnormal heart rhythm can be continuous, or it can come and go. Some individuals, especially patients on medications, may have atrial fibrillation constantly but not have a rapid (>100 heartbeats per minute) rate at rest. Variations of AFib may be termed paroxysmal, persistent, or permanent (these are further described below). AFib is the most common heart arrhythmia. Blood clot formation is a major concern with AFib.

Normal heart contractions begin as an electrical impulse in the right atrium. This impulse comes from an area of the atrium called the sinoatrial (SA) or sinus node, the "natural pacemaker" that causes the normal range of regular heartbeats. Normal heartbeats proceed as follows:

• The electrical impulse originates in the SA node of the right atrium. As the impulse travels through the atrium, it produces a wave of muscle contractions. This causes the atria to contract.
• The impulse reaches the atrioventricular (AV) node in the muscle wall between the two ventricles. There, it pauses, giving blood from the atria time to enter the ventricles.
• The impulse then continues into the ventricles, causing ventricular contraction that pushes the blood out of the heart, completing a single heartbeat.

In an adult person with a normal heart rate and rhythm, the heart beats 50-100 times per minute at rest (not under stress or exercising).

• If the heart beats more than 100 times per minute, the heart rate is considered fast (tachycardia).
• If the heart beats less than 50 times per minute, the heart rate is considered slow (bradycardia).

In atrial fibrillation, multiple sources of impulses other than only from the SA node travel through the atria at the same time. The reason that these sources develop are not completely understood, but cardiac muscles in the pulmonary veins have electrical generating properties and may be one source of these extra impulses.

• Instead of a coordinated contraction, the atrial contractions are irregular, disorganized, chaotic, and very rapid. The atria may contract at a rate of 400-600 beats per minute. The blood flow from the pulmonary veins and the vena cava through the two atria to the ventricles is often disrupted.
• These irregular impulses reach the AV node in rapid succession, but not all of them make it past the AV node. Therefore, the ventricles beat more slowly than the atria, often at fairly fast rates of 110-180 beats per minute in an irregular rhythm.
• The resulting rapid, irregular heartbeat causes an irregular pulse and sometimes a sensation of fluttering in the chest.

Atrial fibrillation can occur in several different patterns.

• Intermittent (paroxysmal): The heart develops atrial fibrillation and typically converts back again spontaneously to normal (sinus) rhythm. The episodes may last anywhere from seconds to days.
• Persistent: Atrial fibrillation occurs in episodes, but the arrhythmia does not convert back to sinus rhythm spontaneously. Medical treatment or cardioversion (electrical treatment) is required to end the episode.
• Long-standing persistent: continuous AFib for more than 12 months
• Permanent: The heart is always in atrial fibrillation. Conversion back to sinus rhythm either is not possible or is deemed not appropriate for medical reasons. In most cases, the rate is reduced by medications and the patients are placed on anti-clotting medication for their lifetime.

Atrial fibrillation, often called AFib, atrial tachyarrhythmia, or atrial tachycardia, is one of the very common heart rhythm disorders.

• It affects mostly people older than 60 years. People older than 40 have about a 25% chance of developing AFib in their lifetime.
• The risk of developing atrial fibrillation increases as we get older.

For many people, atrial fibrillation may cause symptoms but does no harm.

• Complications like blood clot formation, strokes, and heart failure can arise, but appropriate treatment reduces the chances that such complications will develop.
• If treated properly, atrial fibrillation infrequently causes serious or life-threatening problems.

Atrial fibrillation may occur without evidence of underlying heart disease. This is more common in younger people, about half of whom have no other heart problems. This is often called lone atrial fibrillation. Some of the causes that do not involve the heart include the following:

• Thyroid (overactive thyroid)
• Alcohol use (holiday heart or Saturday night heart, a condition of AFib, ventricular tachycardia, or other cardiac arrhythmia usually triggered by some holiday-related event such as increased alcohol drinking or discontinuing medications; the condition often subsides once the triggering behavior is ceased)
• Pulmonary embolism (a blood clot in the lungs)
• Pneumonia

Most commonly, atrial fibrillation occurs as a result of some other cardiac condition (secondary atrial fibrillation).

• Heart valve disease: This condition results from developmental abnormalities people are born with or can be caused by infection or degeneration/calcification of valves with age.
• Enlargement of the left ventricle walls: This condition is called left ventricular hypertrophy.
• Coronary heart disease (or coronary artery disease): This results from atherosclerosis, deposits of fatty material inside the arteries that cause blockage or narrowing of the arteries, interrupting oxygen delivery to the heart muscle (ischemia).
• High blood pressure: This condition is known as hypertension.
• Cardiomyopathy: This disease of the heart muscle leads to congestive heart failure.
• Sick sinus syndrome: This refers to improper production of electrical impulses because of malfunction of the SA node in the atrium of the heart.
• Pericarditis: This condition refers to inflammation of the sac surrounding the heart.
• Myocarditis: This condition causes inflammation of the heart muscle.
• Advancing age: The older a person is above age 40, the higher the risk.
• Heart attack: damaged heart tissues
• Lung diseases: decreased oxygen levels
• Sleep apnea: decreased oxygen levels
• Viral infections: myocarditis
• Stress: increased oxygen demand
• Prior heart surgery: damaged heart tissue

Atrial fibrillation frequently occurs after cardiothoracic surgery or procedures, but often resolves in a few days.

For many people with infrequent and brief episodes of atrial fibrillation, the episodes are brought on by several triggers. Because some of these involve excessive alcohol intake or skipping medications, this is sometimes called "holiday heart "or "Saturday night heart." Some of these people are able to avoid episodes or have fewer episodes by avoiding their triggers. Common triggers include alcohol and caffeine in susceptible individuals.

Although some women present with symptoms of chest pain, many women will not present with chest pain.

Symptoms of atrial fibrillation vary from person to person.

• Several people have no symptoms.
• The most common symptom in people with intermittent atrial fibrillation is palpitations, a sensation of rapid or irregular heartbeat. This may make some people very anxious. Many people also describe an irregular fluttering sensation in their chests. This irregular fluttering sensation is due to the irregular rapid ventricular response (RVR) of the ventricles to the rapid irregular atrial electrical activity.
• Some people become lightheaded or faint.
• Other symptoms include weakness, lack of energy or shortness of breath with effort, and chest pain or angina.

There are a few patients who have potentially life-threatening AFib symptoms that need immediate attention and intervention with electric cardioversion. The symptoms and signs are as follows:

• Decompensated congestive heart failure (CHF), shortness of breath
• Hypotension (low blood pressure)
• Uncontrolled chest pain (angina/ischemia)

Individuals should call for treatment within 24 hours if they have atrial fibrillation that comes and goes, have previously been evaluated and treated, and are not experiencing chest pain, shortness of breath, weakness, or fainting.

Patients should call their doctor or cardiologist if they have persistent atrial fibrillation while on medical therapy for the condition if symptoms worsen or new symptoms such as fatigue or mild shortness of breath occur.

Patients should call their doctor or pharmacist if they have questions about medications and dosages.

Call 9-1-1 for emergency medical services when atrial fibrillation occurs with any of the following:

• Severe shortness of breath
• Chest pain
• Fainting or lightheadedness
• Weakness
• Very rapid heartbeat or palpitations
• Low blood pressure

Not all heart palpitations are atrial fibrillation, but a continuing feeling of heart fluttering in the chest together with a fast or slow pulse should be evaluated by a doctor or at a hospital emergency department. For example, the patient could be having atrial flutter (rapid, regular electrical impulses of about 250-300 impulses per minute from the atrial tissue causing a rapid ventricular response [RVR] or rapid heartbeat) or a sinus tachycardia.

Picture of atrial fibrillation ECG

The doctor will often begin by asking patients about their medical history to help determine the severity of symptoms. The doctor will assess if any associated factors (for example, alcohol or caffeine intake) may be contributing to the patient's symptoms. The doctor will also listen to the patient's heartbeat and lungs. The evaluation may include the following tests:

Lab tests: There is no blood test that can confirm that a person has atrial fibrillation. However, blood tests may be done to check for certain underlying causes of atrial fibrillation and to rule out heart damage, as from a heart attack. People already taking medication for atrial fibrillation may need blood tests to make sure there is enough of the drug (usually digoxin) in their system to work effectively. Blood tests that may be done to rule out other conditions include:

• Complete blood cell count (CBC)
• Markers for heart injury or stress (enzymes such as troponins and creatine kinase [CK] and BNP)
• Digoxin drug level (in patients taking this medication)
• Prothrombin time (PT) and international normalized ratio (INR) (For those taking warfarin [Coumadin] to prevent blood clotting, these tests show how well the drug is working to lower the risk of a blood clot forming in the heart or elsewhere.)
• Serum electrolytes to evaluate sodium and potassium levels
• Thyroid function tests for hyperthyroidism

Stress test: While you exercise, doctors run tests on your heart.

Chest X-ray: This imaging test is used to evaluate for complications such as fluid in the lungs or to estimate heart size.

Echocardiogram or transesophageal echocardiogram: This is an ultrasound test that uses sound waves to make a picture of the heart while it is beating.

• This test is done to identify problems in heart valves or ventricular function or to look for blood clots in the atria.
• This very safe test uses the same technique used to check a fetus in pregnancy.

Ambulatory electrocardiogram (Holter monitor): This test involves wearing a monitor like that used for an ECG for a period of time (usually 24-48 hours) to try to document the arrhythmia while people go about their everyday activities.

• The device is worn for 24-48 hours and is named a Holter monitor.
• The test may be used if symptoms come and go, and ECGs do not reveal the arrhythmia or other problems that could lead to similar symptoms of AFib.

Event recorder: This device that can be worn for 1-2 weeks and records the heart rhythm when it is activated by the patient; it is like a Holter monitor but only records heart rhythms when activated by the patient.

Electrocardiogram (ECG or EKG): This is the primary test to determine when an arrhythmia is atrial fibrillation. The ECG can help the doctor distinguish AFib from other arrhythmias that may have similar symptoms (atrial flutter, ventricular tachycardia, or runs of ventricular tachycardia). The test can also sometimes reveal damage (ischemia) to the heart, if there is any.

The following is an illustration showing the usual ECG tracing from a patient with AFib.

Rapid heart rate ECG of a patient with atrial fibrillation. SOURCE: Image reprinted with permission from Medscape.com, 2012.

Doctors who treat atrial fibrillation include

• internists,
• hospitalists,
• emergency room physicians,
• cardiologists, and
• electrophysiologists (a subspecialty of cardiology).

In making the diagnosis, a patient's doctor will consider the severity of symptoms and whether they are new or have been going on for some time. The patient may be referred to a specialist in heart disorders (cardiologist) during this evaluation. Choice of treatment for atrial fibrillation depends on the type of AFib, the severity of symptoms, the underlying cause, and the patient's overall health. General guidelines for AFib treatment are available, but most doctors modify guidelines to best treat the individual, so treatment is patient-specific. The goals for treatment for AFib are to reset the heart rhythm, control the heart rate and to reduce or prevent blood clots.

There is no effective home treatment for atrial fibrillation while it is occurring. However, if the doctor recommends lifestyle changes or prescribes medicine, follow his or her recommendations exactly. Lifestyle changes may prevent AFib associated with holiday heart. In addition, careful adherence to medication at home may also prevent many episodes of AFib. This is the only way to see whether the medical treatment works or needs adjustment.

Treatment for atrial fibrillation traditionally seeks three goals: to slow down the heart rate, to restore and maintain normal heart rhythm, and to prevent blood clots that may lead to strokes.

• Cardiac rate control: The first treatment goal is to slow down the ventricular rate, if it is fast.
  • If patients experience serious clinical symptoms, such as chest pain or shortness of breath related to the ventricular rate, the health care professional in the emergency department will try to decrease the heart rate rapidly with intravenous (IV) medications.
  • If patients have no serious symptoms, they may be given medications by mouth.
  • Sometimes patients may require more than one type of oral medication to control the heart rate.
• Restore and maintain normal cardiac rhythm: About half of the people with newly diagnosed atrial fibrillation will convert to normal rhythm spontaneously in 24-48 hours. However, atrial fibrillation typically returns in many patients.
  • As already mentioned, not everyone with atrial fibrillation needs to take medication to maintain normal rhythm.
  • The frequency with which arrhythmia returns and the symptoms it causes partly determine whether individuals receive rhythm-controlling medication, which is usually termed anti-arrhythmia medication.
  • Medical professionals tailor each person's anti-arrhythmic medication(s) carefully to produce the desired effect, a normal cardiac rhythm.
  • Most of these medications cause unwanted side effects, which limit their use. These medications should be discussed with a doctor.
• Prevent clot formation (strokes): Stroke is a devastating complication of atrial fibrillation. Blood clots can form in the atria when their motility is impaired as in AFib. Stroke can occur when a piece of a blood clot formed in the heart breaks off and travels to the brain, where it blocks blood flow.
  • Coexisting medical conditions, such as hypertension, congestive heart failure, heart valve abnormalities, or coronary heart disease, significantly increase the risk of stroke. Age older than 65 years also increases the risk of stroke.
  • Many people with atrial fibrillation take a blood-thinning, anti-clotting drug called warfarin (Coumadin) to lower this risk of stroke and heart failure. Warfarin blocks certain factors in the blood that promote clotting. Acutely, the initial blood thinner is IV or subcutaneous heparin to thin a patient's blood rapidly. Then a decision is made whether they need oral warfarin.
  • People at lower risk of stroke and those who cannot take warfarin may use aspirin. It may be used in conjunction with Plavix. Aspirin is not without its own side effects, including bleeding problems and stomach ulcers.
  • Clopidogrel (Plavix) is another medication that is also used by many physicians to prevent clot formation in cardiovascular diseases, including AFib.
  • Other drugs that may be used by some cardiologists include enoxaparin (Lovenox), dabigatran (Pradaxa), and rivaroxaban (Xarelto). The choice of these drugs which are used to reduce the chance of clot formation in patients with chronic AFib is often determined by the patient's problems with Coumadin and the preference or experience of the cardiologist with these drugs.

Cardioversion (also termed defibrillation or electrical cardioversion): This technique uses electrical current to "shock" the heart back to normal sinus rhythm with an electrical current. This is sometimes called DC cardioversion. Prior to cardioversion, many patients undergo a sonogram of the heart to determine if any clots are present.

• Cardioversion is done by connecting a device called an external defibrillator to the chest with patches or paddles.
• When this is performed in a hospital, an anesthetic is usually given first so the patient is sedated and asleep during the procedure because the electrical discharge is painful.
• Cardioversion works very well; most people convert to sinus rhythm. It is most successful if the atrial fibrillation is new (that is, hours, days, or a few weeks). For many, however, this is not a permanent solution because the arrhythmia often comes back.
• Cardioversion increases the risk of stroke and, thus, usually requires pretreatment with an anticoagulant medication.

Cardioversion with drugs: Cardioversion occurs when anti-arrhythmic drugs administered orally or by IV to help restore a normal heart rhythm. This is usually done in the hospital with continuous heart monitoring.

Catheter ablation (radiofrequency [RF] ablation) is a catheter-based technique that electrically burns/destroys some of the abnormal conduction pathways in the atria using radio waves.

• A catheter is threaded into the atria and delivers radiofrequency energy (heat), which interrupts (ablates) a portion of the abnormal electrical conduction pathway. This inactivates the abnormal pathway to provide more consistent flow of electrical impulses from the SA node. The technique is also termed radiofrequency ablation.
• In atrial fibrillation, RF ablation is currently best reserved for patients who have tried anti-arrhythmic medications without success or who cannot take these medications. Current success rates are in the 60%-70% range. However, serious complications associated with the procedure can occur (for example, loss of effective electrical activity in the atria), and these need to be discussed carefully with the doctor before undergoing this procedure.
• In some patients, most of the electrical activity in the atria needs to be destroyed. Consequently, such patients require a pacemaker (see below) to make the heart's ventricles contract in a more normal manner.
• In 2011, the FDA approved AtriCure (an ablation system) for the treatment of atrial fibrillation in patients undergoing open concomitant coronary artery bypass graft (CABG) surgery and/or valve replacement or repair.
• Another technique to treat AFib is cryoablation surgery where a catheter is threaded into the atrium, placed adjacent to veins causing abnormal atrial electrical activity, and freezes the venous tissue to halt the activity.

Pacemaker: A pacemaker is an electronic device that prevents slow heartbeats and may reduce the likelihood of atrial fibrillation in a small number of patients. The artificial pacemaker takes the place of the "natural pacemaker," the SA node, supplying electrical impulses to keep the heart beating in a normal rhythm when the SA node no longer can.

• The pacemaker is usually implanted in both the right atrium and right ventricle. The goal is to override the patient's own atrial fibrillation electric impulses with a new atrial electrical pacemaker. A minority of patients are offered this technique currently. This is a more complex technique and device, and no long-term data regarding success are available yet.
• A pacemaker is occasionally used in conjunction with radiofrequency ablation of the AV node, which disconnects the atria from the ventricle so rapid heart rates cannot be conducted to the ventricles. The ablation creates complete heart block (no connection between atrial electrical activity and atrial contractions and ventricular contractions), and the ventricle contractions become dependent on the artificial electrical pacemaker in the right ventricle for synchronized and regular contractions between the atria and ventricles.
• Some machines and devices in a person's environmental surroundings can interfere with the production of electrical impulses by a pacemaker. For example, airport security devices may deactivate some pacemakers. People need to become familiar with which types of devices may have this effect on their pacemaker and avoid those devices. The patient's doctor who places the pacemaker and the device maker should educate the person about the device use, limitations, and potential complications. Patients should not be hesitant to ask any questions they may have about the device.
• If you have a pacemaker, always carry an identification card that explains this. It may be necessary to present this identification when going through airport security and ask to be hand searched as some security machines may inactivate pacemakers. Patients should always tell any medical or dental personnel that they have a pacemaker.

The choice of medication depends on the type of atrial fibrillation diagnosed, the underlying cause, other medical conditions that contribute to the patient's overall health, and other medications. Ironically, many anti-arrhythmia medications may induce abnormal heart rhythms.

Anti-arrhythmia (anti-arrhythmic) medications include:

• Miscellaneous anti-arrhythmia medications: These drugs control the heart rhythm rather than the rate. They reduce the frequency and duration of atrial fibrillation episodes. They are often given to prevent the return of atrial fibrillation after cardioversion. The most used drugs are amiodarone (Cordarone, Pacerone), sotalol (Betapace), propafenone (Rythmol), and flecainide (Tambocor). Overall, these drugs are 50%-70% effective.
• Beta-blockers: These drugs slow the heart rate by decreasing the rate of the SA node and by slowing conduction through the AV node. Therefore, the heart's demand for oxygen is decreased, and the blood pressure is stabilized. Examples include esmolol (Brevibloc), atenolol (Tenormin), propranolol (Inderal), or metoprolol (Lopressor, Toprol XL).
• Calcium channel blockers: These drugs also slow heart rate by mechanisms similar to those of beta-blockers. Verapamil (Calan, Isoptin) and diltiazem (Cardizem) are examples of calcium channel blockers.
• Digoxin (Lanoxin): This drug decreases the conductivity of electrical impulses through the AV node, but onset of action is slower than beta-blockers and calcium blockers. Digoxin is currently used primarily in patients with associated heart disease, such as a poorly functioning left ventricle.
• Dofetilide (Tikosyn): This is an oral antiarrhythmic drug that must be initiated in the hospital over a three-day period. Hospitalization is needed to closely monitor the heart rhythm during the initial dosing period. If the atrial fibrillation responds favorably during the initial dosing, a maintenance dose is established to be continued at home.
• Other medications: There are many other drugs in use, and they are prescribed to individualize the treatment of AFib. Other drugs can include ibutilide (Corvert), dronedarone (Multaq), and quinidine (Cardioquin, Quinalan, Quinidex, Quinaglute); others may be used rarely.
• Herbs: Some herbal companies claim cures of atrial fibrillation with their product, but the data to support these claims is questionable and not acceptable to most researchers.

Other drugs are used to help patients avoid blood clot formation that may lead to strokes or additional health problems. The decision to utilize other drugs can be augmented by the CHADS2 (also termed CHA2DS2-VASc) score that assigns points to various conditions (congestive heart failure, hypertension, age, diabetes, and previous stroke) in an AFib patient. The higher the points, the more likely the patient is to develop a stroke; some clinicians use this score to help determine what other drugs may help their patients with AFib avoid a stroke.

• Warfarin (Coumadin): This drug is an anticoagulant (blood thinner). It reduces the ability of the blood to clot. It lowers the risk of an unwanted blood clot forming in the heart or in a blood vessel. Atrial fibrillation increases the risk of forming such blood clots. It is extremely important to follow the exact dosing prescribed and to have regular blood tests (International Normalized Ratio [INR]) when recommended by the doctor. Patients are urged to keep these important appointments to reduce their risk of blood clot formation or the risk of having an excessive tendency to bleed.
• Eliquis: This new drug is also utilized to prevent stroke and is like to dabigatran (Pradaxa) and rivaroxaban (Xarelto).
• Aspirin and clopidogrel (Plavix): These are two commonly prescribed drugs used to reduce the chance of clot development in AFib patients, especially if patients cannot tolerate Coumadin; they also have been used in short-term treatments while a patient is undergoing evaluation for clot formation.
• Heparin and enoxaparin (Lovenox): These similar drugs have been used in short-term treatment of AFib patients; occasionally, Lovenox has been used by some physicians for longer term treatment.
• Dabigatran (Pradaxa): This thrombin inhibitor is approved for prevention of strokes and thrombus in nonvalvular AFib. There is some controversy about this new drug causing increased heart problems.
• Rivaroxaban (Xarelto): This factor Xa inhibitor is approved for the prevention of strokes and embolisms associated with nonvalvular AFib; dosing is related to creatinine clearance (CrCl) levels (kidney function).

The above is an overview of the many drugs that doctors may choose to treat AFib. However, everyone is unique, so the treatments vary depending on the medical condition of the patient (for example, presence of a pacemaker or compromised renal function). Those interested can see extensive guidelines for various patients in the American Heart Association journal Circulation.

Before the development of catheter ablation, open heart surgery was done to interrupt conducting pathways in both atria. This is called the surgical maze procedure. Maze surgery is usually considered in patients who need some other type of heart surgery, such as valve repair or coronary artery bypass surgery. Another procedure termed left atrial appendage closure can be used. In this procedure, a device is inserted through a catheter into a small sac in the left atrium. The device seals the sac and helps prevent clot formation in the left atrium.

If patients have no other ongoing heart problems and medications succeed in controlling the patient's heart rate, the patient may be sent home from the emergency department. This is often done after consultation with the patient's doctor or cardiologist. Patients should follow up with their health care professional within 48 hours.

If the heart rhythm does not convert to normal by itself, the patient may need electrical cardioversion or defibrillation.

• Patients in atrial fibrillation longer than 48 hours may need three weeks of treatment with an anticoagulant medication, such as warfarin, before cardioversion and usually for at least four weeks after.
• Anyone with underlying heart disease or those who do not respond to rate-controlling treatment may require hospitalization and a consult with a cardiologist.
• Patients undergoing surgery (pacemaker implantation) may require rehabilitation.

Risk factors for AFib include the following:

• Age (as you age, risk increases)
• Heart disease
• High blood pressure
• Family history
• Obesity
• Excessive alcohol consumption
• Many other chronic medical conditions (for example, chronic lung or kidney disease, diabetes, sleep apnea)

Individuals who do not have atrial fibrillation can lower their chance of getting this arrhythmia by minimizing risk factors. This includes minimizing the risk factors for coronary heart disease and high blood pressure listed below.

• Do not smoke.
• Maintain a healthy weight.
• Make nutritious, low-fat, or nonfat foods the basis of a lifestyle; some physicians suggest increasing a person's intake of fish oil, fiber, and vegetables -- a heart-healthy diet.
• Take part in moderately strenuous physical activity for at least 30 minutes every day.
• Control (reduce) high blood pressure and high cholesterol.
• Use alcohol in moderation (maximum of one to two drinks per day), if at all.
• Avoid caffeine and other stimulants as much as is possible.

If patients have atrial fibrillation, their health care professional may prescribe treatments for the underlying cause and to prevent future episodes of atrial fibrillation. These treatments might include any of the following (see Medical Treatment for more information):

• Medications
• Cardioversion
• Pacemaker
• Radiofrequency ablation
• Maze surgery

In general, the outlook for most individuals with AFib is good to fair, depending on the cause of the disease and how well the patient responds to treatment. The most dangerous complication of atrial fibrillation is stroke.

• Someone with atrial fibrillation is about three to five times more likely to have a stroke than someone who does not have atrial fibrillation.
• The risk of stroke from atrial fibrillation for people aged 50-59 years is about 1.5%. For those aged 80-89 years, the risk is about 30%.
• Warfarin (Coumadin), when taken in appropriate doses and monitored carefully, reduces this risk of stroke by over two-thirds.
• NOACs (New or Novel Oral Anticoagulants) may help prevent heart-related clot formations.
• It is important to know that clinical trial data have shown that individuals can live with atrial fibrillation with a controlled heart rate -- for example, with medications plus Coumadin -- just as long as other people in normal sinus rhythm (AFFIRM trial).

Another complication of atrial fibrillation is heart failure.

• In heart failure, the heart no longer contracts and pumps as strongly as it should.
• The very rapid contraction of the ventricles in atrial fibrillation can gradually weaken the muscle walls of the ventricles.
• This is uncommon, however, because most people seek treatment for atrial fibrillation before the heart begins to fail.

Patients with complications of stroke or heart failure have a more guarded outcome than those without complications. However, for most people with atrial fibrillation, relatively simple treatment dramatically lowers the risk of serious outcomes. Those who have infrequent and brief episodes of atrial fibrillation may need no further treatment other than learning to avoid the triggers of their episodes, such as caffeine, alcohol, or overeating.

The following lifestyle changes and habits are recommended:

• Exercise regularly.
• Eat heart-healthy foods.
• Reach and then maintain a healthy weight.
• Stop smoking.
• Check blood pressure; maintain a normal blood pressure.
• Keep cholesterol levels low.
• Exercise moderation in alcohol intake.
• Take medications as prescribed.
• Keep follow-up doctor appointments.